In certain military missiles, for example, external air foils are connected to internal controls. This arrangement necessarily involves a penetration of the missile skin by one or more control shafts or rocker arms and, the penetration of the missile skin destroys the integrity of the electromagnetic radiation shield. In order to block any stray electromagnetic radiation which might enter the missile through the opening and interfere with proper missile operation, a shielded annular seal has been devised to close the space around the control shafts.
The seals currently being used for this purpose are made of sponge rubber covered with a woven wire mesh, the ends of which must be woven together by hand. No means of mass producing these parts has yet been devised and the hand made parts are subject to a wide variation of dimensions. Because such hand made parts have been found to be unacceptable for their purpose, other methods have been sought which would produce an acceptable product.